[PATCH] pwm: samsung: do not set manual update bit in pwm_samsung_config

[PATCH] pwm: samsung: do not set manual update bit in pwm_samsung_config

[Ajay Kumar]

pwm_samsung_config sets manual update bit via call to
pwm_samsung_enable even when the channel is already running.
This causes noticable flickers on display if we try to change
the backlight value from 0 to MAX, continiously.

So, we remove the call to pwm_samsung_enable from
pwm_samsung_config to avoid the flicker and this change doesn't
harm normal working since the pwm_bl core already takes care of
calling pwm_samsung_enable whenever needed.

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
---
 drivers/pwm/pwm-samsung.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
index d66529a..ba6b650 100644
--- a/drivers/pwm/pwm-samsung.c
+++ b/drivers/pwm/pwm-samsung.c
@@ -335,9 +335,6 @@ static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
 	writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
 
-	if (test_bit(PWMF_ENABLED, &pwm->flags))
-		pwm_samsung_enable(chip, pwm);
-
 	chan->period_ns = period_ns;
 	chan->tin_ns = tin_ns;
 	chan->duty_ns = duty_ns;
-- 
1.8.3.2

Re: [PATCH] pwm: samsung: do not set manual update bit in pwm_samsung_config

[Ajay kumar]

This is a simpler version of https://patchwork.kernel.org/patch/3113001/

On Mon, May 12, 2014 at 8:26 PM, Ajay Kumar <ajaykumar.rs@samsung.com> wrote:
> pwm_samsung_config sets manual update bit via call to
> pwm_samsung_enable even when the channel is already running.
> This causes noticable flickers on display if we try to change
> the backlight value from 0 to MAX, continiously.
>
> So, we remove the call to pwm_samsung_enable from
> pwm_samsung_config to avoid the flicker and this change doesn't
> harm normal working since the pwm_bl core already takes care of
> calling pwm_samsung_enable whenever needed.
>
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> ---
>  drivers/pwm/pwm-samsung.c | 3 ---
>  1 file changed, 3 deletions(-)
>
> diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
> index d66529a..ba6b650 100644
> --- a/drivers/pwm/pwm-samsung.c
> +++ b/drivers/pwm/pwm-samsung.c
> @@ -335,9 +335,6 @@ static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
>         writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
>         writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
>
> -       if (test_bit(PWMF_ENABLED, &pwm->flags))
> -               pwm_samsung_enable(chip, pwm);
> -
>         chan->period_ns = period_ns;
>         chan->tin_ns = tin_ns;
>         chan->duty_ns = duty_ns;
> --
> 1.8.3.2
>

Re: [PATCH] pwm: samsung: do not set manual update bit in pwm_samsung_config

[Tomasz Figa]

Hi Ajay,

On 12.05.2014 16:56, Ajay Kumar wrote:
> pwm_samsung_config sets manual update bit via call to
> pwm_samsung_enable even when the channel is already running.
> This causes noticable flickers on display if we try to change
> the backlight value from 0 to MAX, continiously.
> 
> So, we remove the call to pwm_samsung_enable from
> pwm_samsung_config to avoid the flicker and this change doesn't
> harm normal working since the pwm_bl core already takes care of
> calling pwm_samsung_enable whenever needed.
> 
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> ---
>  drivers/pwm/pwm-samsung.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
> index d66529a..ba6b650 100644
> --- a/drivers/pwm/pwm-samsung.c
> +++ b/drivers/pwm/pwm-samsung.c
> @@ -335,9 +335,6 @@ static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
>  	writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
>  
> -	if (test_bit(PWMF_ENABLED, &pwm->flags))
> -		pwm_samsung_enable(chip, pwm);
> -
>  	chan->period_ns = period_ns;
>  	chan->tin_ns = tin_ns;
>  	chan->duty_ns = duty_ns;
> 

Reviewed-by: Tomasz Figa <t.figa@samsung.com>

Best regards,
Tomasz

Re: [PATCH] pwm: samsung: do not set manual update bit in pwm_samsung_config

[Thierry Reding]

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On Mon, May 12, 2014 at 08:26:21PM +0530, Ajay Kumar wrote:
> pwm_samsung_config sets manual update bit via call to
> pwm_samsung_enable even when the channel is already running.
> This causes noticable flickers on display if we try to change
> the backlight value from 0 to MAX, continiously.
> 
> So, we remove the call to pwm_samsung_enable from
> pwm_samsung_config to avoid the flicker and this change doesn't
> harm normal working since the pwm_bl core already takes care of
> calling pwm_samsung_enable whenever needed.
> 
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> ---
>  drivers/pwm/pwm-samsung.c | 3 ---
>  1 file changed, 3 deletions(-)

Applied, thanks.

Thierry

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